PSB M4U TW1 Earphones Review

They may not be the most accurate or transparent transducer around but considering the technology involved along with their compact design, the results are quite an achievement. I was never bored or fatigued while listening to these and the musicality factor was well above par. This is all available at a very friendly price that makes these a favorable alternative to competing models that rely on their name more than the substance or quality of what they offer.

I first listened to a pair of these nifty in-ear monitors at the 2018 AXPONA show. I had a short session demoing to them with help from none other than Paul Barton himself. I was sufficiently impressed by what I heard that I immediately requested a review pair.

These “earphones” as PSB calls them are wireless Bluetooth in-ear monitors (IEM’s). The M4U TW1 is a single driver per channel design featuring one large 6 mm dynamic driver per channel. Based on what I heard at AXPONA, I was quite interested how these new models would fare over an extended evaluation period.

These IEM’s are a compact and stylish design. They wrap around the pinnae of the user’s ears so the battery/amp/Bluetooth compartment rests comfortably behind the ear. I like this so much more than the obtrusive-looking wireless earbuds that poke out of the side of your head. The PSB’s design is more stable feeling and lets the heavier part of the IEM rest on your outer ear which is much more comfortable for extended use. It also creates a more stable fit when you are walking or jogging.

The drivers are 6 mm (1/4”) single-driver dynamic designs, one per each channel. I like the simplicity of the design and can think of no reason a driver of this size would not be able to cover the entire audible range.

The only method to play music over the PSB M4U TW1’s is by way of Bluetooth. They have advanced A2DP technology which provides smooth and musical response from all the playback devices I tried.

They have lithium ion batteries with a claimed playback time of up to five hours.

The M4U TW1’s have touch-sensitive controls on each side that can be used to play, pause, skip, and answer phone calls. There is an included mic that is used for fielding phone calls without having to take off the IEM’s.

I also want to make special note that the units are clad in a soft rubber material that further enhances the comfort factor. Lastly, the IEM’s are water resistant making them workout-ready!

The M4U TW1’s come with a clam shell carrying case, a USB splitter cable, and three pairs of eartips. I always use the large eartips and so those were the ones I installed.

I charged them fully before pairing. The pairing process was a little frustrating for me the first time I did it. I wound up having to do a reset on them before they would lock on to my iPhone 10. Once paired correctly, I never had any issues getting them to work on each subsequent power up.

The way it works is you pair one channel first and then the other connects as a slave to the first. Later, whichever one you fire up first becomes the master and the other becomes the slave irrespective of the order you initially paired them.

The pairing and power control is by way of an on/off toggle on each channel. These toggles have accompanying LED’s beneath the rubber skin. They communicate by way of various flashing schemesand colors which was cool but I sometimes couldn’t see the LED’s very well. So a brighter LED would be useful.

The earphones have a sultry female’s voice that provides status updates like low battery, paired, master, slave, etc. This was a very nice and luxurious touch.

Once I had them up and running, I did most of my listening to Tidal but I also enjoyed music files that were stored on my phone. I paired them with my PC and tablet to see if that made any difference. I didn’t hear any significant improvement so most of my listening impressions below were made with my iPhone.

The very first thing that jumped out about the sound of these IEM’s was the excellent bass. I’m not really a bass addict but I like tuneful, low-distortion bass. One issue I have with most headphones and IEM’s is that they may have good bass response qualities from an objective standpoint but by virtue of the fact that the sound is directed largely straight into your ear canal, you miss out on all the tactile cues associated with music playback in a room. You don’t feel it in your chest or pants legs. Somehow the PSB M4U TW1’s were able to give me a greater sense of bass slam as if I were in a room and not just keeping the audio exclusively in the cranial realm.

It wasn’t “low distortion” as I mentioned above because there is bass distortion already in the recording. So the PSB’s faithfully passed what was on the recording, distortion and all; just as it should be.

The great bass didn’t come at the expense of any other part of the audible band. This is important – the PSB M4U TW1’s let you have it all. A good example of this quality came around with “Rat Race”. The cymbals, guitars, and vocals all came through in balance with no audible smearing or undue inter-modulation. In fact, I really loved all that I heard because the sound retained the balance and presentation that drew me to this album over 40 years ago. This is a bigger feat than you may suspect since a lot of albums I have on vinyl start to sound like some sort of unduly processed and EQ’d bastardization of the original when they get re-released on a digital medium. It takes contributions all around for this effect to be avoided and I credit the PSB M4U TW1’s as playing a major role in my ability to be taken back in time to enjoy this album in ways that were fully reminiscent of the original.

Jim Lauderdale released two new albums on August 3, 2018. Well one of them was new and the other was recorded in 1979 but was just released this month. I listened to both albums over the PSB M4U TW1’s and they offer an interesting contrast in recording technology.

The 1979 effort was a collaboration, a “collusion” if you will, between Lauderdale and Roland White. In this case, there was collusion indeed and we have the evidence via these found tapes. This album was recorded in Earl Scruggs’ basement and it features all acoustic instrumentation. The warm and natural sound of this recording is its mot salient quality. That the music is fabulous and the performances rare makes this record a real treasure to enjoy. It’s my cup of tea and the PSB M4U TW1’s helped draw me in ever further.

What stands out to me is how White’s mandolin is presented with excellent clarity and dynamic richness. The leading edges of the notes were clean and realistic. The two men’s voices were front and center with excellent clarity and a very natural tonal balance.

Contrast that with Mr. Lauderdale’s all new 2018 release “Time Flies”. The prolific singer-songwriter says that “Time Flies” is a very different sounding album from what he has done before. The title track is first up and you notice straight away how his voice has matured significantly. This song is a Southern rock ballad. I was immediately engaged and just let the music wash all over me (in an abstract sense of course). The message in this song is pretty powerful and the PSB M4U TW1’s stepped aside and let me feel the emotion that was all wrapped up in there.

The whole sound of this album had much more full and extended frequency response than the 1979 effort. The new album also sounded more engaging at first with instruments that seemed more realistic but on further evaluation, the sound of the newer album was in fact significantly more processed and in the long run, the instruments on the older album were more true to the source.

The PSB M4U TW1’s had sufficient transparency to let me hear this difference.

At first blush, the sound of the piano isn’t quite as transparent as I get over my reference headphone set up. But it isn’t expected to be as my reference system is valued at approximately 45 times the price of the PSB M4U TW1’s.

In the case of this piano work, I was engaged and entertained completely. That is one of the paradoxes of high end audio, the sound need not be perfect for the music to move the listener. The sound just needs to have an appropriately musical presentation. This was how I came to view the PSB M4U TW1’s – they were not the most accurate or transparent ‘phones in the world but they were always engaging, musical, and downright “fun”. They were quite enjoyable in their own right indeed.

Still I couldn’t help but compare the PSB M4U TW1’s to my uber high end set up. One point of difference involved the sound of Mr. Gould’s humming. I could clearly hear his humming over both systems but the humming was much more discernible and free of background noise on my high end set up.

Furthermore, the PSB M4U TW1’s do not separate individual notes as well as my high end headphones. I wouldn’t say they are congested, but just that the separation between notes is somewhat foreshortened. This is in some ways a pleasant effect even though it isn’t the most accurate sound I’ve heard.

PSB claims a battery life of up to 5 hours. I never really timed them but they would not last for a whole workday. This does not bother me as I can’t listen to music non-stop all day. At least not over headphones. And it must be taken in context how this is in fact and incredible achievement considering each unit contains a Bluetooth receiver, amp, battery, and driver. Their ability to work for 5 hours is therefore quite amazing. I just wish they would charge up a little faster. They take about two hours to fully charge which means a little more down time than I would hope for.

One final observation – these are not noise-cancelling ‘phones and the ear tips are silicone (vs. comply foam) so they may not isolate well enough for many people to use on a plane. I found them perfectly acceptable for use on a plane for movie watching especially when I turned them up enough to render the background noise more or less moot. But if you want to listen to music, a pair of noise-cancelling headphones would be the appropriate choice in lieu of ear buds.

The PSB M4U TW1 EARPHONES are wireless in-ear monitors with the latest Bluetooth technology. They are very musical with weighty bass response. I highly recommend these over competing models from other brands.

I really enjoyed my time evaluating these incredible little IEM’s. I am just amazed at the audio quality that’s on tap from these highly miniaturized electronics. We have all predicted the future in one way or another but if you had told me fifty years ago that something like this would even be possible I would have called you a loon. Well guess who the loon is now!

Seriously, though, the PSB M4U TW1’s impressed me right out of the gate. They proved to be sufficiently musical to hold my attention over long listening sessions. I never got tired or fatigued by them. The comfort level with these is actually off the charts – the wrap-around design and soft rubber finish contributing to this experience.

I highly recommend these to anyone who is looking to enhance their enjoyment of mobile musical listening. They are perfect for the new breed of smartphones and tablets. Plus they really pump out great bass while their water-resistant design means they won’t be bothered if you get caught in a shower while out and about.